Apparatus for making printing plates



Nov. 30, 1926. 1,608,544

H. E. WOODWARD I APPARATUSFOR MAKING PRINTING PLATES i v 1923 a Sheets-Sheet 1 lm/snroe f/t'. W000 WARD H. E. WOODWARD APPARATUS FOR MAKING PRINTING PLATES Nov. 30 1926.

Filed may 21. 1923 s Sheets-Sheet 2 QQ Q aw n //-/Vt'/YTOR hf 5. 14 000 w/wa Arromsys on o z m t f Q A 3 Q P Y B Nov. 30 1926.

H. E. WOODWARD APPARATUS FOR MAKING PRINTING PLATES Fild mav 1.92s

3 Sheets-Sheet s /HVH r02 /1. E. W000 WA RD B Y I Arrow/ways Y Patented Nov. 39, 1926.

UNITE STATS All HAROLD E. WOODVTARD, OF UNIVERSIIY CITY, M'ISSQURI:

APPARATUS FOR MAKING PRINTING PLATES.

Application filed May 21,

5 which the individual elements of a print ng plate may be secured together..

he present invention is intended for use particularly in making electrotypes, or more properly stated, to secure the individual ele- 10 ments of an electrotype together. As. is

well known, an electrotype is usually composed of a pair of plates, namely, a fac ng plate and a backing plate. These plates are permanently secured together and prior to 1 this invention various means have been employed to accomplish this attachment.

The main object of this invention to evolve a method and produce an apparatus by the use of which the facing plate and backing plate of an electrotype may be spot welded together, whereby said plates may be very accurately and securely connected together.

Pr or to this invention the members of printing plates have been secured together in various ways, such, for instance, as by screws, or by sweating, but neither of these methods has proved entirely successful, the screw method'being atime-consuming one, 39 and the sweating process warping the the use of the method and apdisclosed herein, the members of a .it 1 plate are secured together in much c-ss time than heretofore consumed, and the union between said members is much more accurate and firm.

lVith the foregoing and other objects in view, the invention comprises the novel con struction, combination and arrangement of parts hereinaft more specifically described and illustrated in the accompanying drawings wherein is shown the preferred embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appendec.

I is a side elevation of my improved welding apparatus.

FigfII is a plan ,view of vthezuaprwatus shown in Fig I.

Fig. III is a fragmentary longitudinal section, showing the means for balancing the movable arm of my improved apparatus.

Fig. IV is a section on line IV I iT oti Fig. III.

Fig. V 15 a front elevation of my improved apparatus.

Fig. VI is a fragmentary section; showing the mechanism which permits the movable arm of my apparatus to be swung horizontally. I

Fig. VII is an enlarged section on rm VII-VIIof I. I I

In the drawings, A designates my im proved welding. machine which comp a suitable frame It composed'of a base memher 1, pairs of vertical meinbers and -3 extending upwardly from sa d base member 1, and an approximately l i-shap d. frame 5 supported by the vertical'members 2 and 3 atthe upper ends thereof. Supported by the vertical members 3 and I is a metallic plate 6, said plate, as willhereinafter appear, being intended to function one of the electrodes of my'im'proved welding apparatus. The plate 6 is insulated from the frame 13 of the apparatus by means of insulating material. 7 (Fig. V}.

Located atthe rear of the U-shaped frame- 5 is a vertical bearing 8 which is adapted to rece ve ,a vertical stud shaft 9, said stud shaft having secured to it at its upper end a member 10 provided with a bifurcated portion 11. The member 10 is secured to the stud shaft 9 by means of a p n 12 and said stud shaft is 1 rovided at its lower end with a col ar 13, said collar being fixed to said stud shaft and bearingagainst the lower face of the bearing 8 whereby said stud shaft is prevented from being moved upwardly out of said bearing 8. Theiinemb 10 is separated slightly fr m the top face 1 the bearing 8, as shown in VI, and a plurality of anti frict ion balls 14 arranged,

in a suitable cage 15 are interposed bet-wee:

said bearing 8 and member 10. From the foregoing it is plain that the member 10 capable of oscillatory movement relative to the bearing 8, the stud s .ft 9 osc lla ng within said bearing 8, and the anti-friction halls reducing the friction between said member 10 and said bearing 8 to a minimum.

Pivotally arranged between the upwardly extending arms of the b furcated portion ll of the memberi 10 is a pair of members 16' spaced apart one from the other, said members being normally arranged appr' Ximate- 1y at right angles to the arms of said bifurcated portion 11 of the member 10. Secured to the lower face of each of the members 16 is a pair of bearings 17, each of the bearings on one of said members being in transverse alinement w th a bearing on the oppositely disposed member 16. Supported by each pair of transversely alined bearings is a rod 18 upon which is rotatably mounted an anti-friction roller 19, said rollers being intended for a purpose to be hereinafter set forth.

Supported by the members 16 is a pair of members 20, said members 20, like the members 16, being; spaced apart one from the other. As will be seen by referring to F III of the drawing, each of the members 16 supports one of the members 20, and said members 20 extend rearwardly beyond said members 16. Extending from one of the members 20 to the associated member 20 at a point immediately above the rear portion of the members 16 is a transverse rod 21 upon which is rotatably mounted an anti-friction roller 22 similar to the anti-friction rollers 19 already described.

Interposed between the members 16 is an arm 23, said arm resting upon the anti-friction rollers 19 as shown in Fig. 111, and the roller 22 contacting with the top face there of. The arm 23 it will be noticed is arranged to slide longitudinally of the members 16, the rollers 19 and 22 being intended to permit free movement of said arm relative to said members 16, and said arm being provided with a handle 2% whereby said arm may be conveniently moved. Supported by the arm 23 at the forward end thereof is an electrode 25, the arm 23 being provided with an aperture which receives said electrode and said arm being split between said aperture and its outer end whereby said electrode may be gripped in place in said aperture by the end portions of said arm being drawn together by the bolt 26.

In view of the mechanism that has been described, it is apparent that the electrode 25 is capable of movement to any part of the top face of the electrode 6, the arm 23 which supports said electrode being movable longitudinally of the members 16 whereby said electrode 25 is movable transversely of the plate 6, the member 10, members 16 and arm 23 being capable of oscillatory movement with relation to the bearing 8 whereby said electrode 25 is permitted to move longitudinally of the electrode 6, and the members 16 and arm 23 being pivotally secured to member 10 at the pointindicated by the reference character 27 whereby said electrode may be moved toward or away from said electrode 6.

In the operation of the apparatus disclosed herein, the universally movable arm 23 which supports the electrode 25 is depressed so that said electrode may contact with the work on the electrode 6, and when the downward pressure is withdrawn from arm 23 it is, of course, desirable that the outer end thereof, together with the electrode carried thereby, shall move upwardly away from the work without eifort on the part of the operator. It is apparent that if a fixed counterbalance weight were used the downward pressure necessar to move the electrode agai st the work would increase as said electrode 25 is moved toward the pivotal point 27, and to eliminate this constantly changing pressure I employ an automatically adjusted counterbalance weight which will now be described. designates a counterbalance weight pro vided with rollers 30 which operate on and are supported by the m abers 20, said counterbalance weight being -.ngcd to move longitudinally of said members 20 towart d away from the pivotal point of the members 16. Arranged between the members 26 at one end thereof is a sprocket wheel 31 men red on a rotatable shaft 32 which extends transversely between said members 20 and is sup ported thereby. Arranged at the opposite ends of the members 20 is a similar sprocketwheel 33 mounted on a rotatable shaft 3-! supported by said members 20. The counterbalance weight 29 is provided at each of its ends with an L-shapcd member 35, said l.- shaped members being secured to said counterbalance weight Ill). 36 designates a sprocket chain which operates over the sprocket wheels in themanner illustrated in 111, one end of said chain being tached to one of the L-shaped members 35 on the counterbalance weight 29 and the other end of said chain being; attached to the L-shaped member at the opposite end of said counterbalance weight. Arranged at one end of the arm 23 is a sprocket wheel which is supported by a suitable bracket, and arranged at the opposite end of said arm 23 is a similar sprocket wheel 38. The sprocket wheel 38 is supported by an angular member 39 which is fixed to the 21111123 and, of come. is movable therewith.

10 designates a sprocket chain which passes over said sprocl zet wheels 37 and 38, one end of said sprocket chain being attached to the members 20 at the point indicated by the reference character 11, and the other end of said sprocket chain being attached to members 20 at the point indicated by the reference character Ill). ranged transversely of the members 20 is a rotatable shaft 53, on which is mounted a pair of sprocket wheels 14, one of said sprocket wheels being in mesh with the sprocket chain 36 and the other sprocket wheel being in mesh with the sprocket chain 4-0 (Fig. IV).

In the operation of the apparatus, assume that the arm 23 is drawn outwardly so that the electrode 25 is located adjacent to the lllll accesses outer edges of the electrode 6. With the arm 23 in this position, the counterbalance weight will be located adjacent to the rear ends of the members so that it will offset the weight of the forwardly projected arm 23. Assume now that the arm 23 is moved inwardly to bring the electrode 25 adjacent to the inner position of the electrode 6, or to L M T a y lIlbQllllQUlclLG point. in this event 11,- is necessary to move the counterbalance welght closer to the pivotal point 27, due to the fact that ti 9 length of the projected portion of the arm is reduced, thereby reducing the weight to be offset. ll hen the arm-23 is moved inwardly, the sprocket wheels 37 and :38 will of course move with said arm and the upper flight of the chain d0 will be moved in the direction indicated by the arrow in Fig. III; in other words, the partial loop formed by the chain 40 is moved toward the left, the loop surrounding the sprocket wheel 3? being shortened, and the loop surrounding the sprocket wheel 38 be ing lengthened. Gne of the spocket wheels 44 on the shaft 43 is in mesh with the chain 40, and the other of said sprocket wheels is in mesh ith the chain 36, consequently .vhen the upper flight of the chain, a0 is moved in the direction indicated by the arrow in Fi Ill the associated sprocket wheel will be rotated, and because the second sprocket wheel 44- meshes with the chain 36 said chain 36 will be moved by'said sprocket wheel 44-, whereby said chain will be caused to travel over the sprocket wheels 31 and thereby causing the counterbalance weight 29 to move longitudinally of tl. members 20. From the foregoing it is plain that the counterbalance weight will always be so positioned as to properly balance the weight of the extended portion of the arm 23.

esignates the primary element of a rmer which may be energized from suitable source to provide very low voltage and very high amperage in the secondary element l6, said secondary elenient in electrical contact with an clongatec bar 47 which extends transversely of the apparatus and with the electrode 6,

The elongated bar 47 is normally spaced apart slightly from the arm 23, as shown in Fig I, and when the arm 23 is orawn downwardly to cause the electrode 25 to contact with the worl: on the electrode 6, said arm 2 will contact with said elongated bar w ereby an electric current is permitted to pass from the secondary element 46,

hrough the elongated bar 47, through the within the opening in the asso-cia 1 be 5i. Interposed between each enlarge tion 52 and the bottom oi? the associated bearing 51 is a coil spring 53, said coil spring beingso arranged that it encircles a portion of the associated member 50. The lower portions ofthe members extend through open-ings in the bottom walls of the bearingsohandeach-lower portion of said members is provided with a pair of collars Fil and 55 spaced apart one from the other for a purpose to be hereinafter set forth.

From the foregoing it is plain that the coil springs 53 exerting an upwarc. pressure against the enlarged portions 52 of the members 50 will retain the elongated bar 47 and the associated'members 50 in such positions that the collars will contact firmly with the bottom faces of the bearings 51, and it is also apparent that when the arm 23 is brought into contact with said elongated bar at? and continues to move downwardly, said elongated bar will move downwardly with said arm, said elongated bar oscillating relative to the members 5%) to correspond to the inclination of the arm 23 whereby a very firm contact is obtained between said bar and said arm. By referring to Fig. VII of the drawin it will be seen that the elongated bar be adjusted toward or away from the 2.1 .n 23 by manipulating-the collars 54, which are in- 11. .1 ternally threaded, on the threaded portions 50 of the members 50.

The arm 23 is capable of contacting with the elongated bar regardless of the horizontal position of said arm, and to compel the elongated bar 47 to move downwardly an equal distance throughout its len employ a pair of arms 56 pivoted at Each of the arms 56 is provided at its outer end with a bifurcated portion 58 which partially surround the adjacent member and each of said bifurcated oortions 58 is provided with a projection 59 which stands inwardly between the collars 54 and on the associated member 50 (Fig. Vii). Th inner end of each of the arms 56 is provided with a curved portion 60 provided with teeth, the teeth on one of said arms being in mesh with the teeth of the other arm. It is apparent from the foregoing that he arm 23 were brought into contact with the elongated bar 47 adjacent to one of its ends and said arm 23 and bar l? depressed, the pivoted arm 56 associated with the member 50 at that side of the bar 47 would be rocked, and because the teeth of said pivoted arm 56 are in mesh with the teeth of the other pivoted arm 56, said second mentionl pivoted arm would be rocked an e-: amount and the opposite end of the clon gated bar 17 would be drawn downwardly a distance equal to the downward move a it of the portion of the elongated bar in contact with the arm 23.

To retain the work in place on the electrode 6 I employ work-holding mechanism which comprises a bar 61 which extends transversely of the apparatus immediately above the e" tTOQlQ 6, said bar being provided at each of its ends with a downwardly extending member 62 havin an L-shaped lower portion 68L Associated with, each downwardly extending member 62 is a guide member 64, each of said guide members be ing provided with an L-shaped groove nto which the L-shaped lower portion or l associated member 62 extends. The guide members ca extend transversely of the electrode 6 at each side thereof, and because of the arrangement described itis plain that the work-holding bar 61 may be moved transversely of said electrode 6, the lxshaped portions of the downwardly e);- tendlng member 62 sliding within the L- shaped grooves 65 of the guide member 6 1.

hach ot the guide members 64 is supported by and secured to a pair of vertical rods 66, said vertical rods 66 being arranged to slide vertically in guide members 67 secured to stationary parts of the apparatus. Secured to the lower ends of the vertical rods 66 is a rectangular connecting member 68, said rectangular connecting member being arranged to slide vertically on the members and 1 which support the electrode 6. Arranged below the rectangular connecting member 68 is a foot lever 69 pivoted at 70 to a member 71, said itoot lever 69 and the rectangular connecting member 68 being connected together by a link 7 2. Secured to each of the vertical members 3 and 1 at a point below the rectangular connecting member 68 is a collar 73, and interposed between said collar and the associated portion of said rectangular connecting member is a coil spring 74h. From the foregoing it is plain that the coil springs 7 L will exert an upward pressure against the rectangular connecting member 68, whereby the work-holding bar 61 will be retained in a raised position. However, it is also apparent that it the foot lever 69 were depressed, said rectangular connection member 68, vertical rods 66 and workholding bar 61 would be drawn downwardly to bring said bar 61 against the work on the electrode 6, the coil springs 7 4; in t ois event being compressed between the downwardly moving rectangular connecting member and the stationary collars 73. To permit the bar 61 to be locked in a lowered position,

I employ an arm 75 provided with teeth 76. The foot lever 69 is provided with a projection 77 against which the arm 75 is drawn by a coil spring 7 8. The arm 75 is mounted on an oscillatory shaft 79 mounted in bearings 80 secured to the frame of the apparatus, and said shaft 79 has secured to it a foot lever 81. In operation, when the foot lever 69 is depressed, the projection 7 7 on said foot lever will be drawn along the teeth 76 of the arm 75, and it is plain when the downward movenzent of said foot lever 69 ceases one of he teeth '76 will the projection 77 on the foot lever 69 and pre vent the coil springs 7% from drawing the foot lever 69 upwardly. To release the foot lever 69 when it is held in a lowered position, it is only necessary to depress the toot le 81 whereby the arm 75 will be drawn a from the projection 77, thus releasing the foot lever 69 and permitting the coil springs 74 to return the bar 61 to its raised position.

In moving the work-holding bar 61 rela tive to the electrode 6, it is possible that the operator may grasp said bar at a point acent to one of its ends, and in this event that end of the bar against which the pressure was exerted would move faster than the other end of said bar, thereby causing the L-shaped portions of the members 62 of said bar to bind in the associated grooves 65. To prevent the foregoing, I provide the bar 61 with a longitudinally extending shaft 82 which is supported in bearings 83 secured to said bar 61. Secured to each end of the shaft 82 is a gear wheel 83, which meshes with a rack S-'r secured to the adjacent guide member or. The L-shaped portions of the member 62 operating within the L-shaped grooves 65 will hold the gear wheels 83 in mesh with the racks 84, and it is plain that even though the bar 61 is grasped very close to one of its ends and pressure applied at that point to more said bar the gear wheel 83 at that end would be rotated, and as said gear wheel is mounted on the shaft 83 which supports a like gear wheel both gear wheels will be rotated an equal amount, hence all portions of the bar 61 will receive the same forward or rearward movement.

In the operation of my device, the members of the printing plate are pro erly assembled and are placed on the electrode 6. The work-holding bar is then located immediately above said printing plate and the foot lever 69 is depressed to engage the printing plate and hold same firmly against the electrode, whereupon said foot lever is locked in the depressed position by the toothed arm 75. The arm 23 is then moved to a position where the electrode 25 is located immediately above the printing plate and the forward end or said arm is depressed to cause said electrode 25 to contact with the work and to cause said arm to contact with the elongated bar e7.

The contact of the elongated bar47'and the arm 23 will permit an electric current to pass from the primary element of the transformer to the secondary element thereof, through the bar 47, arm 23 and electrode 25to the printing plate, thence through said printing plate to weld the members thereof together, then to the electrode 6 and back to its source.

To prevent the front end of the arm 23 from being raised too high bythe counterbalance weight 29,1 employ an adjustable stop 86 supported by a stationary part of the apparatus, said adjustable stop being so arranged that the upper end thereof will be engaged by said arm 23 to limit its movement in one direction.

lVhile the arm 23 may be moved longitudinally of the apparatus by grasping the handle 24 and imparting the movement cirectly to the arm, it is apparent that said arm may be moved by rotating the hand wheel 87.

It is sometimes found desirable in welding machines to provide some means for cooling one or the other of the electrodes, and it is apparent that the electrode 25 of my apparatus may be cooled in any suitable manner.

In the use of my improved apparatus I have found that the metal of the plates is slightly raised at the welding points, but these raised points are very easily removed. by means of the ordinary routing machine.

I claim:

1. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode in the form of a flat plate,a universally movable electrode arranged adjacent to said fixed electrode and spaced apart therefrom, said fixed electrode beingadapted to receive a printing plate in electrical contact therewith, and said movable electrode being adapted to be moved into electrical contact with said printing plate, means whereby electric current is caused to pass into said fixed elec trode, and controlling means whereby said current is permitted to or prevented from passing to said movable electrode comprising a contact member movable with said movable electrode, and a second contact member with which said first mentioned contact member is adapted to contact.

2. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode inthe form of plate, a universally movable electrode 'd' fixed -elec trode in, said fixed elec- V "PF il i plate in "electrical contact therewith, and said movable electrode being adapted "to be moved into electrical contact -with said printing plate, means whereby electric current is caused to pass into said fixed elec- Lu LL-NU =ranged ad acent to ca 'ced ap art "there trode, and controlling means whereby said current is permitted to or prevented from passing-to said movable electrode comprising a contact member movable with said movable electrode and an elongated-contact member with which said first mentioned contact member is adapted to contact when said 'll-lSt mentioned contact member is in various horizontal positions.

An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode, a universally movable arm arranged adjacent to said fixed electrode and spaced apart therefrom, a second electrode supported by said movable arm, said fixed electrode being adapted to receive a printing plate in electrical contact therewith and said universally movable arm being adapted to be moved so that the electrode supported thereby may be brought into electrical contact with said printing plate, and means whereby an electric current is caused to pass from one of said electrodes through the printing plate to the other electrode to weld the members of said printing plate together.

4. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode, a pivoted and longitudinally movable arm arranged adjacent to said fixed electrode and spaced apart therefrom, a second electrode supported by said pivoted arm, said fixed electrode being adapted to receive a printing plate in electrical contact therewith and said second mentioned electrode being adapted to be moved into electrical contact with said printing plate, means whereby an electric current is caused to pass from one electrode through said printing plate to the other electrode to weld the members of said printing plate together, and means comprising a counterbalance weight movable longitudinally with respect to said pivoted arm to ward and away from the pivotal point of said arm whereby said arm is balanced in various positions.

5. An apparatus for making printing plates composed of a plurality of members,

comprising a fixed electrode, a pit oted frame arranged above said fixed electrode and spaced apart therefrom, an arm supported by said pivoted frame and movable longitudinally with relation thereto, a sec 'ond electrode supported by said arm, said lixed electrode bein adapted to receive a printing plate in electrical contact thereith and said second mentioned electrode being adapted to bejmoved into electrical jcontact with said printing plate, a counterbalance-"weight rnounted on said pivoted frame,- means associated with {said pivoted H ame, imovabl'e arm and counterbalance wei g-ht "whereby said counterbalance weight is movable toward and. away from the pivllD rec

otal point of said pivoted frame to balance said movable arm, and means whereby an electric current is caused to pass from one of said electrodes, through said printing plate to the other electrode to weld the members of said printing plate together.

6. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode, a pivoted frame arranged above said fixed electrode and spaced apart therefrom, an arm supported by said pivoted frame and movable longitudinally vith relation thereto, a second electrode supported by said arm, said fixed electrode bein adapted to receive a printing plate in electrical contact therewith and said second mentioned electrode being adapted to be moved into electrical contact with said printing plate, a counterbalance weight mounted on said pivoted frame, means comprising le connectors associated with said pivoted frame, movable arm and counterbalance weight whereby said counterbalance weight is movable toward and away from the pivotal point oft said pivoted "l ame to balance said movable arm, and means wnereby an electric current is caused. to pass from one Oil said electrodes, through said printing plate to the other electrode to weld the members oi? said printing plate together.

7. An apparatus for making printing plates coi'npesed of a plurality of members, comprising a fixed electrode, a movable electrode adjacent to said fixed electrode and spaced apart therefrom, said fixed electrode being adapted to receive a printing plate in electrical contact therewith, and said movable electrode being adapted to be moved into electrical contact with said plate, means whereby said printv e may be held in place on said tired electrode comp a work-holding member etrrtending transversely of said 1 electrode and means whereby said 1.. work-holding member may be drawn downwardly against the printi plate on said fixed electrode, and means hereby an eleccaused to pass from one of L ough l linting plate, a weld the members gether. 8. An apparatus for making printing olates composed of a plur lity of members, prising a fixed electrode, a movable adja lb to said lined electrode paced therefrom, said fixed electode being adapted to receive a printing plate in electrical contact therewith, an

said movable electrode beingadapted to be moved intov electrical contact with said printing plate, means comprising a workholding member extending laterally ofsaid fixed electrode whereby said printing plate maybe held in place on said fixed electrode, said work-holding member being movable parallel to said fixed electrode and vertical- 1y with relation thereto, means whereby said work-holding member may be drawn downwardly against said printing plate to hold same in place on said fixed electrode, and means whereby an electric current is caused to pass from one of said electrodes through said printing plate to the other electrode to weld the members of said printing plate together.

9. An apparatus for making printing plates composed oi a plurality of members comprising a fixed electrode in the form oi a fiat plate, a movable electrode adjacent to said fixed electrode and spaced apart there-- from, said fixed electrode, being adapted to receive a printing plate in electrical contact therewith and said movable electrode being adapted to be moved into electrical contact with said printing plate, work-holding mechanism comprising oppositely disposed guIde members, a work-holding member e2;- tending longitudinally of said fixed electrode, said worh-holdng member being slidably secured to said oppositely disposed guide members, and means whereby said guide members and the work-holding member sccured thereto may be drawn downwardly to cause said work-holding member to engage the printing plate on said fixed electrode, and means whereby an electric current is caused to pass from one electrode, through said printing plate to the other electrode to weld the members of said printing plate together;

10. An apparati is for making printing plates composed Or a oluralniy of members comprising a fixed electrode in the form ot a Hat plate, a movable electrode adjacent to said fixed elect-rode and spaced apart therefrom, said fixed electrode being adapted to receive a printing plate in electrical contact therewith and said movable electrode being adapted to be moved into electrical contact with said pri' plate, work-holding niecl1a1n-"-i comprising oppositely disposed guide members having slots formed therein, a worleholdmg member extending longitudinally of said fixed electrode, down Ill) said electrodes through said printing plate to the other electrode to weld the members o'l said printing plate together.

11. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode in the form of a flat plate, a movable electrode adjacent to said fixed electrode and spaced apart therefrom, said fixed electrode being adapted to receive a printing plate in electrical contact therewith and said movable electrode being adapted to be moved into elect-rical contact with said printing plate, work-holding mechanism comprising oppositely disposed racks, pinions meshing with said racks, a shaft connecting said pinions, a worl holding bar secured to said shaft, ant. means wiereby said worleholding bar may be drawn downwardly against the printing plate on said fixed electrode to hold said printing plate in a fixed position, and means whereby an electric current is caused to pass from one of said electrodes, through said printing plate to the other electrode to weld the members of said printing plate together.

12. An apparatus for making printing plates composed of a plurality of members, con'iprising a fixed electrode, a movable electrode adjacent to said fixed electrode and spaced apart therefrom, said fixed electrode being adapted to receive a printing plate in electrical contact therewith and said movable lectrode being adapted to be moved into electrical contact with said printing plate, work-holding mechanism comprising oppo sitely disposed guide members having l..- shaped slots formed therein, racks on said guide members, pinions meshing w'th said rac s, a shaft connecting said pinions, a work-holding bar supported by said shaft, said work-holding bar having downwardly extending portions which extend into said L-shaped slots and are slidable therein, and means whereby said guide members and the work-holding bar may be drawn downwardly to hold the printing plate in place on said fixed electrode, and means whereby an electric current is caused to pass from one of said electrodes, through said printing plate to the other electrode to weld the members of said printing plate together.

13. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode, a movable arm arranged adjacent to said fixed electrode and spaced apart therefrom, a second electrode supporte by said movable arm, said fixed electrode being adapted to receive a printing late in electrical contact therewith and said movable arm being adapted to be moved so that the electrode supported thereby may be brought into electrical contactwith said printing plate, means whereby an electric current is caused to pass into said fixed electrode and controlling means whereby said current is permitted to or prevented from passing to said movable arm and the electrode supported thereby, said neans comprising an elongated transversely arranged yieldable contact member pivotally supported and spaced apart from said movable arm,said movable arm being adapted to be moved to contact with and depress said yieldable contact member to cause said electric current to pass from one of said electrodes, through said printing plate to the other electrode to weld the members of said printing plates together, and means whereby the downward movement of said contact member is equal at all points thereof.

14. An apparatus for making printing plates composed of a plurality of members, comprising a fixed electrode, a movable arm arranged adjacent to said fixed electrode and spaced apart therefrom, a second electrode supported by said movable arm, said fixed electrode bein adapted to receive a printing plate in electrical contact therewith and said movable arm being adapted to be moved so that the electrode supported thereby may be brought into electrical con tact with said printing plate, means whereby an electric current is caused to pass into said fixed electrode, and controlling means whereby said current is permitted to or prevented trom passing to said movable arm and the electrode supported thereby, said means comprising an elongated transversely arranged yieldable contact member, pivotally supported and spaced apart from said movable arm, said movable arm being adapted to be moved to contact with and depress said yieldable contact member to cause said electric current to pass from one of said electrodes, through said printing plate to the other electrode to weld the members of said printing plates together, and means comprising pivoted segments cooperating with said contact member whereby the downward movement of said contact member is equal at all points thereof.

In testimony that I claim the foregoing I hereunto afiix my signature,

HAROLD E, lVQQDlVARD.

ill- 

